Since ancient times, homes, places of worship and other buildings have been decorated through the use of stained glass windows. These windows generally comprise leaded or stained glass members of different shapes and/or colors which together, when placed in a predetermined mosaic form a desired picture or pattern.
While the term "stained glass" is commonly used, it is generally a misnomer. Many coloring methods are and have been employed and the best medieval glass made little use of actual stained glass. Today, plastics are also used in place of glass.
In accordance with classical techniques, these pieces of glass are held together by lead or brass came. Generally, the came comprises a slender grooved lead rod which is used to hold together the panes of glass by being placed between them and being soldered to form the required support structure.
Such work requires a high degree of skill requiring precise cutting of the came to match the pattern, soldering of the came at the points where the metal came member ends meet other members and precise working of the glass into the came. Nevertheless, even with the highest level of skill, imperfections do occur. These imperfections become evidenced by deterioration of the stained glass window structure as the window ages. Deterioration generally takes the form of the introduction of leaks into the structure causing draftiness and the introduction of soot and other dirt into the room in which the stained glass window is located. More seriously, water also will leak through any deterioration or imperfection in the structure. This causes water to accumulate inside the cames causing serious corrosion and eventual disintegration of the structure.
Even without these imperfections, stained glass windows, due to the force of wind, rain and other environmental factors, tend to belly over time, causing further deterioration and compounding problems caused by drafts and leaks.
Still yet another problem with stained glass structures is the fact that they tend to become quite dirty and, because of the delicate nature of the stained glass window, cleaning is a time consuming, tedious and expensive task. This task is often complicated when the particular stained glass used has deep surface texture patterns which also tend to accumulate dirt. Accumulated dirt and other environmental particles also tend to retain moisture for a somewhat longer period of time than a clean window and, accordingly, any corrosion problems will be compounded by the same. This is particularly serious where a particular soldered joint may already be somewhat defective and deterioration of the good part of the joint may result in failure of the same.
In addition to all of the above, since the onset of the Industrial Revolution, acidity of the rain and the presence of other corrosive materials in the environment has introduced a further degree of seriousness to the deterioration of stained glass windows. This aspect is particularly troublesome because of the natural susceptibility of lead and other cam materials to dissolution in the presence of acid.